Dielectric, ferroelectric, and strain properties of lead-free (1−y)BNT–yST ceramics

• DOI: 10.1007/s10854-020-03133-z
• Publication Date: 2020-02-25T16:02:42Z
• Authors: Amir Ullah; Aman Ullah; Mateen Ullah; Aurang Zeb; Zeeshan Khan; M. Ikram; Hamd Ullah; Ill Won Kim
• Keywords: 0103 physical sciences; 01 natural sciences

Lead-free ceramics (1−y) (Bi1/2Na1/2)TiO3–ySrTiO3 (1−y)BNT–yST with y = 0, 0.1, 0.20, 0.25, 0.28, 0.30, and 0.32 were synthesized via a solid-state reaction process. A uniform grain morphology was obtained, and the mean grain size was around 2.0 μm for y = 0, which decreased slightly for y > 0. The undoped compound displayed a crystal structure with rhombohedral symmetry, and increasing amounts of ST gradually transformed the material to cubic phase. The maximum dielectric constant temperature (Tm) was observed to decrease from 305 °C for sample y = 0 to 135 °C for sample y = 0.30. Remnant polarization (Pr) decreased with increasing ST, and the ferroelectric loops narrowed. The coercive field (Ec) was also observed to decrease with enhanced ST content; however, Ec and Pr increased for y = 0.30. The electric field-induced strain gradually increased up to y = 0.28 but decreased for y > 0.28. The loops of strain became slimmer and saturated with increasing ST ratio to attain the maximum dynamic strain of 624 pm/V.